Oliver Glasner believes Crystal Palace's quiet transfer window is catching up with them, following their defeat by Manchester United on Sunday.

The Eagles were beaten at Selhurst Park for the first time in the Premier League this season, after United came from behind to secure a 2-1 victory.

Defeat ended Palace's 12-match unbeaten league streak on home soil, while they missed the chance to go fifth in the table.

Glasner's side were playing their 22nd game in all competitions this season (compared to United's 14th), largely due to their Conference League commitments after winning the FA Cup last term.

Despite their busier schedule, Palace made just five senior signings during the summer transfer window, which shut on September 1. The Eagles also sold talisman Eberechi Eze, though they did keep hold of Marc Guehi amid Liverpool's interest.

Glasner, who was overseeing his 200th game as a coach in Europe's big five leagues, believes the Eagles are paying the price for not adding more depth to the squad.

"If you play European football for the first time in your history, you should invest and not save," he said. "We are doing well, we are still in a good position in the league and in all four competitions.

"I think January is too late [to add more players]. We will have played more than 50% of our games. Everything we are facing now, it's not surprising.

"Everything was pretty clear, and I didn't say anything. But today, I think it is also time to speak about it. We missed a couple of chances in July and August, in the transfer window, to make it easier for us. But again, we will stick together and make it better."

Glasner was also unable to hide his frustration at the manner of Palace's defeat to United, with the hosts having registered 14 shots on goal during the contest, but undone by two set-pieces.

"I don't want to talk about the missed chances," he continued. "If we need more than one minute to be organised for a free-kick, it is our fault. 

"We deserved to have the lead, and then it is about small margins. I can't remember if Manchester United had a chance in open play, but they were really good from set-pieces, and that's why we lost in the end.

"We can find many excuses, we can say fatigue, rotation, many excuses, but the performances, in many parts, was good. Man United have played 50% less games this season.

"The result really hurts at the moment, but we will learn from it. Sometimes, learning hurts."